The present invention relates generally to chucks for use with drills or electric or pneumatic power drivers. More particularly, the present invention relates to a chuck of the keyless type which may be tightened or loosened by hand.
Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools used with such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones, and other cutting or abrading tools. Since the tools may have shanks of varying diameter or may have a polygonal cross-section, the device is usually provided with a chuck that is adjustable over a relatively wide range. The chuck may be attached to a driver by a threaded or tapered bore and may be formed integrally with the drive shaft of the drill.
A wide variety of chucks have been developed in the art. In one form of chuck, three jaws spaced circumferentially approximately 120 degrees apart from each other are constrained by angularly disposed passageways in a body attached to the drive shaft. The chuck is configured so that rotation of the body in one direction with respect to a constrained nut forces the jaws into or away from a gripping relationship with a tool shank. Such a chuck may be keyless if it can be tightened or loosened by manual rotation. Examples of such chucks are disclosed in U.S. Pat. Nos. 5,125,673 and 5,193,824, commonly assigned to the present assignee and the entire disclosures of which are incorporated by reference herein.
In another form of chuck, a nut is axially movably disposed about the chuck body so that axial movement of the nut with respect to the chuck body moves the chuck jaws within their passageways. The nut defines threads on an outer circumferential surface that mate with threads defined on an inner circumferential surface of a sleeve. Rotation of the sleeve with respect to the chuck body moves the nut axially to drive the jaws within the passageways to grip and ungrip a tool. Various configurations of keyless chucks are known in the art and are desirable for a variety of applications.
The present invention recognizes and addresses the foregoing considerations, and others, of prior art construction and methods. Accordingly, it is an object of the present invention to provide an improved chuck for use with a manual or powered driver.
This and other objects are achieved by a chuck for use with a manual or powered driver having a rotatable drive shaft. The chuck includes a generally elongated body having a nose section and a tail section. The tail section is configured to rotate with the drive shaft, and the nose section has an axial bore formed therein. A plurality of jaws are movably disposed with respect to the body to and away from the axial bore. A collar is in axially driving engagement with the jaws and is axially movably disposed with respect to the body so that movement of the collar in a first axial direction drives the jaws toward the axis of the bore and movement of the collar in a second axial direction opposite the first axial direction moves the jaws away from the axis. The collar is configured to receive at least one of the body and a shaft and defines a first surface that faces a second surface defined by at least one of the body and the shaft when at least one of the body and the shaft receives the collar. A collar first surface is tapered in the axial direction with respect to the axis from a first end of the first surface to a second end of the first surface so that a first radial distance between the second surface and the first end is less than a second radial distance between the second surface and the second end. At least one rolling element is disposed between the tapered first surface and the second surface when at least one of the body and the shaft is received by the collar, and defines a diameter greater than the first radial distance and less than the second radial distance so that when the rolling element engages at least one of the body and the shaft, the collar is movable in the first axial direction and so that axial force applied to the collar in the second axial direction wedges the rolling element between the tapered first surface and the second surface.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.